Project 1. Abstract Defining brainstem neuronal pathways for orofacial motor actions This Research Project will define the neuronal phenotypes and their connectivity, i.e., the ?Components and Wiring diagrams, for premotor and higher order, e.g., pre2motor pathways for rhythmic orofacial motor actions. This will reveal the control structure for coordinating motor actions. Primary technologies for this work are transsynaptic viral tracing in both neonates and adult mice, intersectional labeling strategies followed by transsynaptic tracing in adult animals, and intersectional strategies to manipulate neuronal activity in order to infer function. Adult data will be added to the Trainable Texture-based Digital Atlas (Project 5 and Core 2) These data will yield essential circuitry for orofacial exploratory actions. Our five-year horizon is anatomical identification of pre- and pre2motor pathways for key orofacial senses: twitching and directional movement of by the nose, shifts in the position of the mystacial pad driving set point changes, and completion of the circuit for whisking, bobbing of the head. We further consider anatomical circuitry underlying motor control of the tongue for motor actions involved in search or discrimination tasks, along with vocalization. These data provide a set of connections that constrain models for the activation and operation of orofacial exploratory circuitry. They give insight into the operational tradeoffs that nature has made in network design. These data, along with complementary anatomy and electrophysiology data from Research Projects 2 and 3, provide input for a theoretical analyses of the control mechanisms that coordinate different orofacial actions during exploration (Project 4).